Study of the Accuracy of Emission Factors and Emission Estimating Methods Using the DIAL System Summary Results 2011 NAQC 03102011 1 City of Houston Emission Factors Study Results PurposeIntroduction ID: 474318
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Slide1
City of HoustonStudy of the Accuracy of Emission Factors and Emission Estimating Methods Using the DIAL System
Summary Results2011 NAQC - 03/10/2011
1
City of Houston Emission Factors Study ResultsSlide2
Purpose/Introduction
The purpose of the test program is to obtain more information regarding the accuracy of emission factors and emission estimating methods authorized by law and widely used in industry
The National Physical Laboratory (NPL) under contract to the City used differential absorption lidar (DIAL) technology to assess concentrations of benzene and aliphatic hydrocarbons
(C3-C15) at a refinery and chemical plant
The DIAL measured emissions from tanks, a
coker, a waste water treatment process and process unit area emissionsThe measured concentrations were converted by calculation to mass rates which were then compared to emissions calculated by using EPA approved emission factors
2
City of Houston Emission Factors Study ResultsSlide3
Measuring VOC and Benzene Emissions with DIAL
DIAL: Differential absorption lidar, a form of laser radar
Uses an IR laser to measure VOC and a UV laser to measure benzene
Lasers measure the absorption profile across an elevated path to obtain concentration profile
Wind speed sensors are used to measure the wind profile
VOC and benzene emission rates are calculated from the product of gas concentrations and the wind velocity component perpendicular to the DIAL measurement plane
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City of Houston Emission Factors Study ResultsSlide4
Uncertainties Associated with DIAL Measurements
Factors Contributing to UncertaintiesMeasurement uncertainties: instrumental variability in measuring IR and UV absorptions
Concentration uncertainties: uncertainties associated in using absorption data measured at a single wavelength to determine concentrations of VOC and benzene
Wind field uncertainties: associated with applying wind speed data measured at one or two locations to a different elevated location where DIAL absorption is measured
Emissions uncertainties: questions regarding impact of “wake effects” from nearby structure and roadways on calculated emissions rates or emissions from nearby units
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City of Houston Emission Factors Study ResultsSlide5
Sources Studied
Process Area EmissionsAromatics and Benzene Concentration Units (ACU/BEU)Catalytic Reformer - 3 (CR3)Coker
Wastewater TreatmentTanksTank Maintenance
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City of Houston Emission Factors Study ResultsSlide6
Emission Factor Calculations forProcess Area Emissions
Includes the sum of all sources in the area (e.g. tanks, flares, fugitive emissions, cooling water tower) when the DIAL study measurements were made
Calculations were based on approved EPA methodology The temperature used was the monthly average during the month that the DIAL measurements were made
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City of Houston Emission Factors Study ResultsSlide7
Emission Factor Calculations forProcess Area Emissions - Continued
Methods used to calculate emissions for each source type were as follows:
Tanks – EPA’s Tanks 4.0Flares – Measured flow and composition to the flare at 98% combustion efficiency
Fugitive emissions – Emissions were calculating using the LEAKDAS© software.
Cooling water towers –
Measured inlet and outlet concentration data are compared
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City of Houston Emission Factors Study ResultsSlide8
ACU/BEU Area Emissions
Date/Time
DIAL Result (lbs/hour)
Emissions Factor Based Calculations (lbs/hour)
2/12/2010 10:40 -16:40
27 lbs/hour Benzene
3.41
lbs/hour Benzene
2/15/2010 10:18 -15:09
13 lbs/hour Benzene
3.41
lbs/hour
Benzene
3/26/2010 10:53 - 17:05
64 - 65
lbs/hour
VOC
2.49
lbs/hour VOC
8
DIAL results found in the NPL DIAL Report Page 136. For scans
SDP35, NPL DIAL Report Page 65 & SDP36, NPL DIAL Report Page
67.
SDP36
SDP35
City of Houston Emission Factors Study ResultsSlide9
CR3 Area Data
Date/Time
Report Reference
DIAL Result (lbs/hour) VOC
Emissions Factor Based Calculations (lbs/hour)
1/21/2010 13:10 - 15:23
NPL DIAL Report Pages 29, 72 and 79
8
– 12 lbs/hour
20.67 lbs/hour
3/25/2010 10:53 - 16:54
NPL DIAL Report Pages 62, 73 and 80
30 lbs/hour
20.67 lbs/hour
No abnormal conditions were identified for either 1/21/2010 or 3/25/2010
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City of Houston Emission Factors Study ResultsSlide10
Emission Factor CalculationsDelayed Coker Drum De-heading Emissions
Used factors from the Emission Estimation Protocol for Petroleum Refineries, Version 1.0, December 2009,Submitted to: OAQPS, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711,There is only one set of emission factors available; inputs due to varying coke types (e.g. size) are currently not available
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City of Houston Emission Factors Study ResultsSlide11
Coker Area Data
Date/Time
DIAL Result (lbs/hour)
Emissions Factor Based Calculations (lbs/hour)
1/16/2010,
10:58 -17:13 – NPL DIAL Report Pages 16, 72, 75
2 - 3
lbs/hour VOC
0.64 lbs/hour VOC
1/27/2010,
14:27
-
17:09 – NPL DIAL Report Pages 39, 73, 75
2
lbs/hour VOC
0.64 lbs/hour VOC
2/4/2010,
10:17 -
16:50 – NPL DIAL Report Pages 54, 73, 75-76
3 -4
lbs/hour VOC
0.66 lbs/hour VOC
2/11/2010, 11:22
-
16:47 – NPL
DIAL Report Pages 94, 114, 116-117
5 - 27
lbs/hour Benzene
0.0
lbs/hour Benzene
2/17/2010,
10:06 -
16:54 – NPL DIAL Report Pages 108, 114, 117; Reference in NPL report to possible contributions from tanks and the dock
22- 31
lbs/hour Benzene
0.01
lbs/hour Benzene
3/27/2010,
9:58-
16:51 – NPL DIAL Report pages 108, 114, 117
3 - 4
lbs/hour VOC
0.01
lbs/hour VOC
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City of Houston Emission Factors Study ResultsSlide12
General Coker Area
2/11/2010 15:42-15:58 (27 lbs/hr benzene)
Scan 633, LOS2, Benzene from Coker Drums 5 &6 Single Scan, NPL DIAL Report Pages 94, 114 and 117
Note the location and elevation of the plume for potential monitoring applications
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City of Houston Emission Factors Study ResultsSlide13
Coker Area Data - Continued DIAL measured benzene was not consistent with the measured VOC based on the feed composition to the Coker process
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City of Houston Emission Factors Study ResultsSlide14
Wastewater TreatmentEmissions data were calculated with factors from EPA approved wastewater protocols.Flow rates, temperatures and composition data are inputs to the model.
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City of Houston Emission Factors Study ResultsSlide15
Waste Water Treatment-North Effluent Treater Area Data
Date/Time
Report
Reference
DIAL Result (lbs/hour)
Emissions Factor Based Calculations (lbs/hour)
1/25/2010,
10:42 - 12:34
NPL DIAL Report Pages 35, 72 and 80
22
lbs/hour VOC
6.5 lbs/hour VOC
1/30/2010,
12:26 - 17:01
NPL DIAL Report Pages 45, 73 and 80-81
800 - 1200
lbs/hour VOC
15 lbs/hour VOC
2/5/2010,
10:50 - 16:56
NPL DIAL Report Pages 57, 73 and 81
400 - 600
lbs/hour VOC
11.5
lbs/hour VOC
2/9/2010,
10:42 - 16:57
NPL DIAL Report Pages 88, 114 and 115-116
6
lbs/hour Benzene
0.019 lbs/hour Benzene
2/13/2010
,12:53
- 16:42
NPL DIAL Report Pages 100, 114 and 116
4
lbs/hour Benzene
0.20 lbs/hour Benzene
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City of Houston Emission Factors Study ResultsSlide16
Waste Water Treatment-South Effluent Treater Area Data
Date/Time
Report Reference
DIAL Result (lbs/hour)
Emissions Factor Based Calculations (lbs/hour)
2/1/2010, 12:16 - 17:05
NPL DIAL Report Pages 49, 73 and 82
23 - 27
lbs/hour VOC
5.88
lbs/hour VOC
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City of Houston Emission Factors Study ResultsSlide17
Waste Water Treatment-North Effluent Treater Area Data (continued)
22 lbs/hr VOC
Alkane
32.8 lbs/hr Total VOC based on composition data (NPL DIAL Report Page 135)
1/25/2010, 10:42-12:34 (NPL DIAL Report Pages 35, 72 and 80) DAF skimmer was not functioning normally during this test.
17
SDP12 NPL DIAL Report Page 36
City of Houston Emission Factors Study ResultsSlide18
Waste Water Treatment-North Effluent Treater Area Data (continued)
1/30/2010, 10:42-12:56 (NPL DIAL Report Pages 35, 72 and 80)800-1200 lbs/hr VOC Alkane Plume was 99% Alkane based on composition data (NPL DIAL Report Page 136)
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SDP12 NPL DIAL Report Page 48
City of Houston Emission Factors Study ResultsSlide19
Tank Emission Factor Based Calculations
Used EPA’s Tanks 4.0 method to determine tank emission factorsTank operating parameters used in Tanks 4.0 to calculate tank emissionsMaximum tank throughput and temperature of contents Vapor pressure based on maximum temperature
External factors such as solar absorption factors were obtained from EPA’s Tanks 4.0
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City of Houston Emission Factors Study ResultsSlide20
Tank EmissionsFloating Roof Tanks D-350, D352, D-371, D-370, D-380 and D-381
Tank
Date/Time
Report Reference
Tank
DIAL Result (lbs/hour)
Emission Factor Based
Calculations (lbs/hour)
D-350
02/12/10
16:49-17:46
NPL DIAL Report Pages 97, 114 &117-118
25
lbs/hour Benzene
0.03 lbs/hour Benzene
D-352
03/22/10
12:29-16:45
NPL DIAL Report Pages 110, 114 & 118
5 lbs/hour Benzene
0.02 lbs/hour Benzene
D-351
02/12/10
16:49-17:46
NPL DIAL Report Pages 97, 114 & 117-118
25 lbs/hour Benzene
0.09 lbs/hour Benzene
D-371
02/15/10
11:00-17:00
NPL DIAL Report Page 103
Not Available
0.02 lbs/hour Benzene
D-370
02/15/10
11:00-17:00
NPL DIAL Report Page 103
Not Available
0.02 lbs/hour Benzene
D-380
02/15/10
11:23-17:13
NPL DIAL Report Page 103
13 lbs/hour Benzene
0.25 lbs/hour Benzene
D-381
02/15/10
11:23-17:13
NPL DIAL Report Page 103
13 lbs/hour Benzene
0.30 lbs/hour Benzene
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City of Houston Emission Factors Study ResultsSlide21
Tank EmissionsTanks AP 16 &17 and G-324
Type
Tank
Date/Time
Report Reference
Tank
DIAL Result (lbs/hour)
Emission Factor Based
Calculations (lbs/hour)
Fixed
AP-16
01/15/10
13:42-16:50
NPL DIAL Report Pages 12, 72 & 74
51 lbs/hour VOC
0.14
lbs/hour VOC
Fixed
AP-17
01/15/10
13:42-16:50
NPL DIAL Report Pages 22, 72 and 74
51
lbs/hour VOC
0.25
lbs/hour VOC
Fixed
AP-17
01/19/10
12:00-14:00
NPL DIAL Report Page 74
43 lbs/hour VOC
0.46
lbs/hour VOC
Floating
G-324
01/14/10
12:32-17:12
NPL DIAL Report Pages 8, 72 and 74-75
16
lbs/hour VOC
0.26
lbs/hour VOC
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City of Houston Emission Factors Study ResultsSlide22
Tank EmissionsDistilling Kerosene Tanks J-327 and J-328
Type
Tank
Date/Time
Report Reference
Tank
DIAL Result (lbs/hour)
Emission Factor Based
Calculations (lbs/hour)
Fixed
J-327
01/22/10
15:53-17:03
NPL DIAL Report Pages 31, 72 & 78
31
lbs/hour VOC
0.14
lbs/hour VOC
Fixed
J-327
01/23/10
10:57-17:06
NPL DIAL Report Pages 33, 72 & 78
5-19
lbs/hour VOC
0.15
lbs/hour VOC
Fixed
J-327
01/28/10 11:23-16:41
NPL DIAL Report Pages 41, 73 & 78
32-33
lbs/hour VOC
0.11
lbs/hour VOC
Fixed
J-328
01/22/10 15:53-17:03
NPL DIAL Report Pages 31, 72 & 78
31
lbs/hour VOC
0.12
lbs/hour VOC
Fixed
J-328
01/23/10 10:57-17:06
NPL DIAL Report Pages 33, 72 & 78
5-19
lbs/hour VOC
0.12
lbs/hour VOC
Fixed
J-328
01/28/10 11:23-16:41
NPL DIAL Report Pages 41, 73 & 78
32-33
lbs/hour VOC
0.16
lbs/hour VOC
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City of Houston Emission Factors Study ResultsSlide23
Tank EmissionsHydrocracker Feed Tanks J-331 and J-332
Type
Tank
Date/Time
Report Reference
Tank
DIAL Result (lbs/hour)
Emission Factor Based
Calculations (lbs/hour)
Fixed
J-331
01/22/10 15:53-17:03
NPL DIAL Report Pages 31, 72 & 78
31
lbs/hour VOC
0.54
lbs/hour VOC
Fixed
J-331
01/23/10 10:57-17:06
NPL DIAL Report Pages 33, 72 & 78
5-19
lbs/hour VOC
0.43
lbs/hour VOC
Fixed
J-331
01/28/10
11:23-16:41
NPL DIAL Report Pages 41, 73 & 78
32-33
lbs/hour VOC
0.06
lbs/hour VOC
Fixed
J-332
01/23/10
10:57-17:06
NPL DIAL Report Pages 41, 73 & 78
5-19
lbs/hour VOC
0.31
lbs/hour VOC
Fixed
J-332
01/28/10
11:23-16:41
NPL DIAL Report Pages 33, 72 & 78
32-33
lbs/hour VOC
0.06
lbs/hour VOC
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City of Houston Emission Factors Study ResultsSlide24
Tank Emissions – D-380 and D-381
February 15, 2010: Tank just south of ACU/BEU complex
Tank D-381: Internal floating roof, Temp 86 deg F, VOC Vapor Pressure 2.4
psia
, Filling at 1.09 ft/hr from 11:47 to 17:00 (No process data for Tank D-380)
DIAL Benzene (lbs/hr) per Scan, LOS2, NPL DIAL Report Page 103
11:23-11:38: 29
11:40-11:58:
18
11:59-12:17:
141
13:35-13:53:
61
13:54-14:12:
53
15:17-15:38:
43
15:46-16:11:
32
16:19-16:37:
21
17:03-17:13:
12
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SDP28 NPL DIAL Report Page 105
City of Houston Emission Factors Study ResultsSlide25
The measurements on 2/8/2010 and 2/10/2010 may be biased low because lowerElevation scan angles may have been partially blocked by structures – NPL DIAL Report
Page 115Tank Emissions
Floating Roof Tanks TOL-913 and TOL-920
Tank
Date/Time
Report Reference
Tank
DIAL
Result (lbs/hour)
Emission Factor Based
Calculations (lbs/hour)
TOL-913
02/08/10
14:15-17:23
NPL DIAL Report Pages 86, 114 & 115
6 lbs/hour benzene
1.15 lbs/hour benzene
TOL-913
02/10/10
9:55-17:05
NPL DIAL Report Pages 91, 114 &115
5 lbs/hour benzene
1.17lbs/hour benzene
TOL-913
03/23/10
10:18-17:05
NPL DIAL Report Pages 112, 114 & 115
25 lbs/hour benzene
1.18lbs/hour benzene
TOL-920
02/08/10
14:15-17:23
NPL DIAL Report Pages 86, 114 & 115
6 lbs/hour benzene
0.83 lbs/hour benzene
TOL-920
02/10/10
9:55-17:05
NPL DIAL Report Pages 91, 114 & 115
5 lbs/hour benzene
0.83lbs/hour benzene
TOL-920
03/23/10
10:18-17:05
NPL DIAL Report Pages 112, 114 & 115
25 lbs/hour benzene
0.83lbs/hour benzene
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City of Houston Emission Factors Study ResultsSlide26
Tank EmissionsFloating Roof Tanks A-310, A-326, A-330, A-332, A333 and A-325
Tank
Date/Time
Report Reference
Tank
DIAL
Result (lbs/hour)
Emission Factor Based
Calculations (lbs/hour)
A-310
01/14/10
12:32-17:12
NPL DIAL Report Pages 8, 72 & 74-75
16 lbs/hour VOC
0.17
lbs/hour VOC
A-326
01/15/10
11:35-13:21
NPL DIAL Report Pages 12, 72 & 74
lbs/hour VOC
0.34
lbs/hour VOC
A-330
01/13/10
12:26-17:36
NPL DIAL Report Pages 6, 72 & 73-74
16-19 lbs/hour VOC
0.45
lbs/hour VOC
A-332
01/13/10
12:26-17:36
NPL DIAL Report Pages 6, 72 &73-74
16-19 lbs/hour VOC
1.27
lbs/hour VOC
A-333
01/13/10
12:26-17:36
NPL DIAL Report Pages 6, 72 & 73-74
16-19 lbs/hour VOC
0.43
lbs/hour VOC
A-325
01/15/10
11:35-13:21
NPL DIAL Report Pages 12, 72 & 74
11
lbs/hour VOC
0.22
lbs/hour VOC
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City of Houston Emission Factors Study ResultsSlide27
Inspection records were checked on all tanks and no abnormal conditions were noted.
The FLIR infrared camera utilizing an optical imagining technology provides a quick and accurate measurement of hydrocarbon emission leaks.
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Tank Emissions -
Continued
Date
Method
Tank
Result (
ppm
= parts per million)
2/9/2010
FLIR IR Camera
A-318
No
emissions detected
2/10/2010
FLIR IR Camera
TOL-913
No
emissions detected
2/16/2010
FLIR IR Camera
D-380
No
emissions detected
2/16/2010
FLIR IR Camera
D-381
No
emissions detected
2/16/2010
Gas Chromatograph
D-380
2.05
ppm
Air sample collected at the tank vents while tank was in the running gauge mode
2/16/2010
Gas Chromatograph
D-381
36.8
ppm
Air sample collected at the tank vents while filling,
0.712
ppm
in static modeCity of Houston Emission Factors Study ResultsSlide28
Tanks TOL-913/TOL-920
28
3/23/2010, 10:18-17:05
(Benzene, 25 lbs/hr) NPL DIAL Report Pages 112, 114 and 115
SDP33 NPL DIAL Report Page 113
City of Houston Emission Factors Study ResultsSlide29
Tank A-318 Maintenance
This tank had been out of service several months before NPL took the DIAL measurementApproximately two inches of heavy low vapor pressure asphalt like material was in the bottom of the tank at the time of the test
Cutter stock had previously been used as part of the cleaning process, but was not in use at the time of the testing
29
City of Houston Emission Factors Study ResultsSlide30
Tank A-318 Maintenance (continued)
Type
Tank
Date
Time
Tank
Emission Factor Based
DIAL Result (lbs/hour)
Calculations (lbs/hour)
Floating
A-318
1/14/2010
15:56-16:08
4,000 lbs/hour VOC
Maintenance activity
Shifting winds and the closeness of the plume to the DIAL may have affected the results
30
Single Scan NPL DIAL Report Pages 8, 72, 74-75
City of Houston Emission Factors Study ResultsSlide31
Tank A-318 Maintenance (continued)
1/14/2010, 15:56-16:08 (4000 lbs/hr VOC Alkane) Single Scan, NPL DIAL Report Pages 8, 72, 74-75
A single scan found the noted emission rate, but scans before and after may have missed this source as the winds shifted and the plume may have been too close to the DIAL.
31
SDP02 NPL DIAL Report Page 11
City of Houston Emission Factors Study ResultsSlide32
Summary of Results
The DIAL method has uncertainty in measurement and uncertainty in converting from concentrations to mass rates. During the time period studied, the mass emissions calculated using recognized and widely used emission factors were lower than the DIAL results. Further study is warranted given the size of the difference in emissions determined by the two methods.
32
City of Houston Emission Factors Study ResultsSlide33
Questions?